The AISWatchMate 750 Receiver does not have a built-in GPS receiver, so there is no connection supplied for an external GPS antenna. The AISWatchMate 750 is designed to work with a stand alone GPS Sensor or can use a data feed from another GPS device on your vessel. The output from the GPS Sensor, or from another GPS device, is connected to the NMEA input port of the AISWatchMate 750.